The present invention generally relates to a data search technique for a processing apparatus.
In enterprise activities, utilization of a large amount of generated business data has become indispensable. A column store database (hereinafter “column store DB”) is known as a database (DB) for efficiently storing and analyzing a large amount of business data. In general, a database includes a table and a table includes a plurality of rows, and a plurality of values corresponding to a plurality of data items (columns) is recorded in each row (such values are hereinafter called “column values”). In the column store DB, a plurality of column values in a plurality of records is stored in an area corresponding to each column. The column store DB can also be stored in a main memory of a server. However, the cost (for example, a bit cost) for the main memory per unit capacity is generally higher than for an external storage apparatus. Thus, in a system that handles a large amount of data, the column store DB is generally stored in an external storage apparatus configured as a HDD or a flash storage.
US Patent Application Publication No. 2012/84278 discloses an in-memory column DB system in which each query in a column store DB of an in-memory type has at least one column predicate, a column required for scan is determined for each query, a plurality of queries is grouped into a scan group based on the determination, and the column predicate is evaluated for the queries of the scan group according to a schedule plan. WO 2015/162752 discloses a storage apparatus which includes a controller and a storage medium, and in which the storage medium includes one or more flash modules having a database operation unit, and the controller receives an operation request on a row store DB to cause the flash module to execute the received operation request on the row store DB.